1. Field of Endeavor
The present invention refers to the field of machining of workpieces by material stripping. It relates to a mobile collecting device for the high-pressure water jet of a water jet tool and also to a method for its operation.
2. Brief Description of the Related Art
It has been known for a long time to use a water jet, which issues under very high pressure from a nozzle, for the machining, especially the cutting, of workpieces. In the case of so-called “abrasive water-jet cutting” (AWJ), water pressures of more than 300 MPa are used in order to produce a water jet, which is laden with abrasive substances, with a jet diameter of typically 1 mm. Such a water jet can be used as a cutting tool which acts in all directions and with which a wide range of metallic and non-metallic materials, with thicknesses of up to 200 mm, can be cut through. In this case, it is important not to only collect and drain off the water of the high-pressure water jet, but especially to render the kinetic energy of the water jet harmless by conversion into thermal energy if this water jet has worked its way through the workpiece and discharged rearwards (downwards) from the workpiece.
In the case of stationary systems, in which the nozzle head of the water-jet tool is movable in a plane in X and Y directions, the mostly plate-form workpiece is fixed on a largely jet-penetrable support base. Beneath the support base, special devices are then arranged over a large area for collecting and rendering harmless the high-pressure water jet which passes through the workpiece (see for example U.S. Pat. Nos. 4,112,797 and 5,295,425).
Compact collecting devices have already been proposed, however, which can be moved together with the water-jet tool and can also be used in the case of confined space conditions at the application site (see for example EP-A2-0 244 966 and EP-A2-0 252 657). In this case, however, it is disadvantageous that the entry areas which are provided for the water jet are very small so that the collecting devices have to be adjusted very accurately to the water-jet tool.
In a prior application of the assignee of this application, it was proposed to use a water-jet tool with turbine rotors and other components of power plants. With the turbine rotors fitted with rotor blades, according to FIGS. 1 and 2, it is a matter of separating the blades 12, which are detachably fastened on the turbine wheels 11 of the rotor 10, from the rotor 10 by cutting up the bolts 17, which are interference-fitted in corresponding holes 16 and connect the blade roots 14, which are beneath the blade platform 13 and recessed in annular grooves 15, to the turbine wheel 11, by a water-jet tool 18 in the longitudinal direction, and then forcing out the bolt sections from the holes 16. The water-jet tool 18, which includes a tool body 19 and an angled nozzle head 20 and is supplied with water via a water feed line 21, is introduced into the interspace between adjacent turbine wheels 11 and 11′ (FIG. 2) for this purpose. If the bolt 17 is cut through in the longitudinal direction, the high-pressure water jet discharges on the other side of the turbine disk 11 into the interspace which exists there and can cause damage if it is not collected and rendered harmless.